A team of experts — including John Keller, project scientist for NASA's Lunar Reconnaissance Orbiter; NASA producer/visualizer Ernie Wright; and space historian Andrew Chaikin — used images of the moon from Apollo 8 and LRO to determine where the Apollo spacecraft was pointed at what time. Their findings are laid out in a video that reconstructs the chain of events that occurred in lunar orbit on Dec. 24, 1968.

To add to the occasion, NASA re-created the "Earthrise" picture — incorporating modern-day lunar imagery from LRO, Earth imagery from NASA's Blue Marble data set, and the cloud patterns documented by the Environmental Science Services Administration 7 satellite on that history-making day. (Use the Flash-based slider-bar gizmo on NASA's Web page to compare the original with the re-creation.)

The Earthrise re-creation is well-timed — not only to mark the anniversary, but to mesh with our Cosmic Log Space Advent Calendar, which has been celebrating imagery of Earth from space on a daily basis during December.

The year 1968 was a tumultuous time marked by war, assassination, civil unrest and deep political division. As the year came to a close, the flight of Apollo 8 gave the nation an occasion to soar. NBC's Brian Williams reports.